His longtime coach, Paul Tetreault, told The Providence Journal that Mr. Pisano had experienced a choking episode last week and suffered severe brain damage after being without oxygen for a significant time.

His family decided to take him off a ventilator Monday night.

Less than two weeks ago, Mr. Pisano completed the Boston Marathon in just over 12 hours. It was the 52d marathon he had finished.

Mr. Pisano was born with a severe form of cerebral palsy, but motivated himself and others with his motto of “impossible is nothing.’’